In any case, what I do not want – close as it is - is a cheap sports/fitness band. What I would like is something very like that :

Rubber wrist band – nice to have, but not mandatory

Rugged & robust – is quite important

Button/cell battery – for small form fit

NO built in apps, e.g. health / fitness

It would be nice if I were able to load my own software. For instance, to vibrate the band remotely, or display messages. What I don’t want is lots of built-in fitness tracker stuff, which is not associated with my system

There is no indication of battery life (although I don’t expect any problems with BTLE)

I would prefer something worn on the wrist, but could live with this

On the plus side it seems easy to program “After you connect to the Bluefruit, you can send commands wirelessly in under 10 minutes”. Also, “Built in over-the-air bootloading capability so we can keep you updated with the hottest new firmware. Use any Android or iOS device to get updates and install them” seems a big plus.

Is there any other cheap (preferably sub $50) wrist wearable which is programmable, preferably with a snap-in coin/cell battery?

[Update] I now have a strong preference for BT 5, rather than v4, but can't seem to find any. The reason being that the BT 5 spec has provisions for proximity, which could save me a lot of effort on triangulation.

Looks great, and is pretty much what I was planing to develop. It uses RFID, though, not BT. I could live with that, although it obviously has to be active RFID, not passive, which dries up the price of the readers. Hmm, I just read further and their readers will also detect BT-LE. I will contact them, as their underlying infrastructure interests me, but I really want to develop the software which acts upon employee location myself (plus maybe also transmit to BT). A great comment - feel free to post it as an answer - but I am still looking for the wearable :-(
– MawgFeb 24 at 8:05